The present invention relates generally to an antenna device, a radio communication device including the antenna device, and a method for transmitting and receiving electromagnetic waves. More particularly, the present invention is related to an antenna device that is adaptable to a variety of conditions.
In modern communication systems, there is an ever increasing demand for making the user devices smaller. This is especially important when it comes to hand portable terminals (terminals), for example mobile phones. The design of the hand portable terminals must permit the terminals to be easily and rapidly manufactured at low costs. Still the terminals must be reliable in use and exhibit a good performance.
It is well known that the size of an antenna is a factor that must be considered in the design of the antenna as it may impact the antenna""s performance. Moreover, the interaction between antenna, phone body and the nearby environment (such as the user) must also be considered when designing the antenna. Additionally, there is often a requirement that two or more frequency bands shall be supported, further adding to the number and complexity of factors to be considered by the antenna designer. To this end, radiating properties of an antenna device for a small-sized structure (such as a hand portable terminal) heavily depend on the shape and size of the support structure of the phone (such as a printed circuit board, PCB) as well as on the phone casing. All radiation properties, such as resonance frequency, input impedance, radiation pattern, impedance, polarization, gain, bandwidth, and near-field pattern are products of the antenna device itself and its interaction with the support structure of the phone and the phone casing. Additionally, objects in the nearby environment affect the radiation properties.
The above considerations require the antenna device to be more compact, versatile while exhibiting good antenna performance. As can be appreciated, the performance of the antenna depends on the design of the terminal in which it is to be used as well as on objects in the nearby environment of the antenna device.
With the above factors in mind, it can be appreciated that the design of a antenna devices in terminals, the antenna is tailored to the characteristics of this specific terminal and to be suited for a xe2x80x9cnormalxe2x80x9d use in a xe2x80x9cnormalxe2x80x9d environment. This means that the antenna device cannot later on be adapted to any specific condition under which a certain terminal is to be used or to suit a different terminal. Thus, each model of a terminal, such as a hand portable phone, must be provided with a specifically designed antenna, which normally cannot be optimally used in any other terminal model or cannot be optimally adapted to a variety of nearby environments.
Accordingly, conventional antenna devices lack the versatility and adaptability that is desirable in modern communication terminals. What is needed, therefore, is an antenna that is more versatile and adaptable, and which affords good performance characteristics in a variety of devices and environments.
What has been stated above is true also with respect to radio communication systems used in other apparatuses than portable phones, such as cordless telephones, telemetry systems, wireless data terminals, etc. Thus, even if the antenna device of the invention is described in connection with portable phones it is applicable on a broad scale in various radio communication apparatuses.
Current solutions include distributed control of antenna segmenst, diversity antennas, and phased array radar systems. However, none of these arrangements provide versatile antenna devices that can be adapted to a wide variety of conditions, especially to conditions in the close-by environment of the device, by controlling a central switching unit.
The present invention is therefore directed to an antenna device, a communication device including the antenna device and a method of receiving and transmitting electromagnetic waves that substantially overcomes one or more of the problems due to the limitations and disadvantages noted above.
It is an object of the present invention is to provide a versatile antenna device for a communication device, which antenna device is adaptable to various conditions and for obtaining desired functions.
It is also an object of the invention to provide an antenna device, which can be adapted in order to suit different communication apparatuses, such as different models of hand portable phones, after it has been mounted in the apparatus.
Another object of the invention is to provide an antenna device, of which certain characteristics are easily controllable, such as radiation pattern, tuning, polarization, resonance frequency, bandwidth, input impedance, gain, diversity function, near-field pattern, connection of antenna elements as receiving/transmitting elements.
An additional object of the invention is to provide an antenna device including switchable antenna elements and which antenna device is easy to manufacture, and exhibits a controllable interaction between the switch and the antenna elements.
A further object of the invention is to provide an antenna device suited to be used as an integrated part of a radio communication device.
A particular object of the invention is to provide an antenna device, preferably for receiving radio waves, including a patch antenna device switchable between at least two different frequency bands.
Accordingly, the invention of the present disclosure relates generally to an antenna device and method for transmission and/or reception of electromagnetic waves. Illustratively, the antenna device includes radiating structure including at least two antenna elements. The at least two switchable antenna elements are connected to at least one switching element, which is connected to a central switching unit. The at least one switching element is capable of selectively connecting and disconnecting the at least two antenna elements.
As a result of the ability to selectively connect/disconnect particular antenna elements, the antenna device of the present invention achieves the desired versatility to enable optimal transmission and reception of electromagnetic signals in a variety of terminals and in a variety of nearby environments.
The invention is described in greater detail below with reference to the embodiments illustrated in the appended drawings. However, it should be understood that the detailed description of specific examples, while indicating illustrative embodiments of the invention, are given by way of example only, since various changes and modifications within the scope of the claims will become apparent to those skilled in the art reading this detailed description.